Application of enhanced extended observer in station-keeping of a quadrotor with unmeasurable pitch and roll angles

In this paper we provide an example of application of the design of a control law that makes use of an enhanced version of the so-called extended observer. The enhancement in question reposes on the extension of a classical Lemma due to Dayawansa to the case of nonlinear systems whose normal form includes time-varying (and measurable) gains. The presented example concerns a station-keeping problem of a quadrotor with unmeasurable pitch and roll angles.